Electrochemical splitting of water to produce hydrogen and oxygen is an important process for many energy storage and conversion devices. Developing efficient, durable, low-cost, and earth-abundant electrocatalysts for the oxygen evolution reaction (OER) is of great urgency. To achieve the rapid synthesis of transition-metal nitride nanostructures and improve their electrocatalytic performance, a new strategy has been developed to convert cobalt oxide precursors into cobalt nitride nanowires through N2 radio frequency plasma treatment. This method requires significantly shorter reaction times (about 1 min) at room temperature compared to conventional high-temperature NH3 annealing which requires a few hours. The plasma treatment significantly enhances the OER activity, as evidenced by a low overpotential of 290 mV to reach a current density of 10 mA cm(-2) , a small Tafel slope, and long-term durability in an alkaline electrolyte.

We have successfully fabricated flexible asymmetric supercapacitors (ASCs) based on acicular Co9S8 nanorod arrays as positive materials and Co3O4@RuO2 nanosheet arrays as negative materials on woven carbon fabrics. Co9S8 nanorod arrays were synthesized by a hydrothermal sulfuration treatment of acicular Co3O4 nanorod arrays, while the RuO2 was directly deposited on the Co3O4 nanorod arrays. Carbon cloth was selected as both the substrate and the current collector for its good conductivity, high flexibility, good physical strength, and lightweight architecture. Both aqueous KOH solutions and polyvinyl alcohol (PVA)/KOH were employed as electrolyte for electrochemical measurements. The as-fabricated ASCs can be cycled reversibly in the range of 0-1.6 V and exhibit superior electrochemical performance with an energy density of 1.21 mWh/cm(3) at a power density of 13.29 W/cm(3) in aqueous electrolyte and an energy density of 1.44 mWh/cm(3) at the power density of 0.89 W/cm(3) in solid-state electrolyte, which are almost 10-fold higher than those reported in early ASC work. Moreover, they present excellent cycling performance at multirate currents and large currents after thousands of cycles. The high-performance nanostructured ASCs have significant potential applications in portable electronics and electrical vehicles.

yields a synergism for the HER. [ 25 ] In accordance with the "volcano plot," the activity for the evolution of hydrogen is a function of the M H (metal hydride) bond strength and exhibits a peak value for metal Pt, which has an optimal M H bond strength. [ 26 ] Therefore, designing a material on the molecular scale which combines an M H-weak metal (Ni) with an M H-strong metal (Mo) is a feasible method to acquire ideal catalysts. Sasaki's group synthesized NiMoN x nanosheets on carbon support [ 21 ] and mixed close-packed Co 0.6 Mo 0.14 N 2 particles [ 20 ] via annealing corresponding precursors under ammonia gas. Both of the materials show the high HER electrocatalytic activity with low overpotential and small Tafel slope. In addition to the pristine activity of the catalysts, a variety of other parameters can limit their performance, such as roughness, conductivity, stability of the catalyst, the attachment of catalysts on electrodes. [ 27 ] In general, hazardous and unfriendly ammonia is applied as nitrogen source for synthesis of metal nitrides from metal oxide precursors at relatively high temperatures (600-800 °C). [ 21,[28][29][30] In addition, this method often results in incomplete nitrifi cation, leading to inferior electronic, mechanical and thermal properties of the as-obtained composites. In this work, we employed a novel method to synthesize 3D porous nickel molybdenum nitride on carbon cloth (NiMoN) by treating electrodeposited NiMo alloy fi lms with N 2 plasma at a relatively low reaction temperature (450 °C) and shorter duration (15 min). The obtained bimetallic nitrides exhibit a 3D porous hierarchical structure with high roughness factor (1050), and outstanding catalytic performance for HER. It is believed that this method can be employed for the synthesis of many other bimetallic nitride nanostructures for applications in battery and supercapacitors.The overall synthesis procedure for the porous NiMoN fi lms on carbon cloth is illustrated schematically in Figure 1 a. First, a dense and shiny grey NiMo alloy fi lm is deposited on commercial carbon cloth (Figure 1 c,f) via optimized pulse-electrodeposition (PED) method. Then, after being treated under N 2 RF plasma at 450 °C for 15 min, a porous and black NiMoN fi lm is obtained (Figure 1 d,g). According to the previous report, [ 31 ] the metal Mo cannot be electroplated from an aqueous solution directly without the assistant of metal Ni. With increasing the molybdenum content, the deposited alloys tend to the amorphous state and an amorphous pattern appears when the content of molybdenum is over 20 at%. [ 32 ] A further increase in the molybdenum content causes crack in the deposited fi lm. Hence, a molybdenum concentration of 20 at% in the alloy is found optimal by tuning the deposition parameters (Supporting The fossil-fuel crisis and the increasing environment issues have triggered the urgent demand for renewable and clean energy sources. Hydrogen is considered as a promising alternative energy carrier to fossil fuels because of its zero ca...

Flexible electronics have gained considerable research interest in the recent years because of their special features and potential applications in flexible displays, artificial skins, sensors, sustainable energy, etc. With unique geometry, outstanding electronic/optoelectronic properties, excellent mechanical flexibility and good transparency, inorganic nanowires (NWs) offer numerous insights and opportunities for flexible electronics. This article provides a comprehensive review of the inorganic NW based flexible electronics studied in the past decade, ranging from NWs synthesis and assembly to several important flexible device and energy applications, including transistors, sensors, display devices, memories and logic gates, as well as lithium ion batteries, supercapacitors, solar cells and generators. The integration of various flexible nanodevices into a self-powered system was also briefly discussed. Finally, several future research directions and opportunities of inorganic NW flexible and portable electronics are proposed.